Conventionally, there is well-known a clip comprising a pin, and a grommet including an insertion hole wherein the pin can be inserted, and forming a plurality of leg pieces by a slit provided in a length direction of a leg portion, and by an insertion of the pin into the insertion hole, the grommet can spread one portion (for example, see paragraph [0008] and FIGS. 1 to 6 in Patent Document 1, and paragraph [0015] and FIGS. 1 to 4 in Patent Document 2).